Fatty acid and lipid profiles in primary human trophoblast over 90h in culture

Acetyl-CoA metabolism maintains histone acetylation for syncytialization of human placental trophoblast stem cells

During pregnancy, placental-fetal nutrient allocation is crucial for fetal and maternal health. However, the regulatory mechanisms for nutrient metabolism and allocation in placental trophoblasts have remained unclear. Here, we used human first-trimester placenta samples and human trophoblast stem cells (hTSCs) to discover that glucose metabolism is highly active in hTSCs and cytotrophoblasts, but during syncytialization, it decreases to basal levels, remaining necessary for fueling acetyl-CoA and differentiation potential. Acetate supplementation could rescue syncytiotrophoblast fusion from glycolysis deficiency by replenishing acetyl-CoA and maintaining histone acetylation, thus rescuing the activation of syncytialization genes. Even brief glycolysis deficiency could permanently inhibit differentiation potential and promote inflammation, which could also be permanently rescued by brief acetate supplementation in vivo. These results suggest that hTSCs retain only basal glycolytic acetyl-CoA metabolism during syncytialization to regulate cell fates via nutrient-responsive histone acetylation, with implications for our understanding of the balance between placental and fetal nutrition.

Synthesis of phospholipids in human placenta

INTRODUCTION

Placental phospholipid synthesis is critical for the expansion of the placental exchange surface area and for production of signaling molecules. Despite their importance, it is not yet established which enzymes involved in the de novo synthesis and remodeling of placental phospholipids are expressed and active in the human placenta.

METHODS

We identified phospholipid synthesis enzymes by immunoblotting in placental homogenates and immunofluorescence in placenta tissue sections. Primary human trophoblast (PHT) cells from term healthy placentas (n = 10) were cultured and exposed to 13C labeled fatty acids (16:0, 18:1 and 18:2 n-6, 22:6 n-3) for 2 and 24 h. Three phospholipid classes; phosphatidic acid, phosphatidylcholine, and lysophosphatidylcholine containing 13C fatty acids were quantified by Liquid Chromatography with tandem mass spectrometry (LC/MS-MS).

RESULTS

Acyl transferase and phospholipase enzymes were detected in human placenta homogenate and primarily expressed in the syncytiotrophoblast. Three representative 13C fatty acids (16:0, 18:1 and 18:2 n-6) were incorporated rapidly into phosphatidic acid in trophoblasts, but 13C labeled docosahexaenoic acid (DHA; 22:6 n-3) incorporation was not detected. 13C DHA was incorporated into phosphatidylcholine. Lysophosphatidylcholine containing all four 13C labeled fatty acids were found in high abundance.

CONCLUSIONS

Phospholipid synthesis and remodeling enzymes are present in the syncytiotrophoblast. 13C labeled fatty acids were rapidly incorporated into cellular phospholipids. 13C DHA was incorporated into phospholipids through the remodeling pathway rather than by de novo synthesis. These understudied pathways are highly active and critical for structure and function of the placenta.

An Integrated Multi-OMICS Approach Highlights Elevated Non-Esterified Fatty Acids Impact BeWo Trophoblast Metabolism and Lipid Processing

Maternal obesity and gestational diabetes mellitus (GDM) are linked with impaired placental function and early onset of non-communicable cardiometabolic diseases in offspring. Previous studies have highlighted that the dietary non-esterified fatty acids (NEFAs) palmitate (PA) and oleate (OA), key dietary metabolites associated with maternal obesity and GDM, are potential modulators of placental lipid processing. Using the BeWo cell line model, the current study integrated transcriptomic (mRNA microarray), metabolomic, and lipidomic readouts to characterize the underlying impacts of exogenous PA and OA on placental villous trophoblast cell metabolism. Targeted gas chromatography and thin-layer chromatography highlighted that saturated and monounsaturated NEFAs differentially impact BeWo cell lipid profiles. Furthermore, cellular lipid profiles differed when exposed to single and multiple NEFA species. Additional multi-omic analyses suggested that PA exposure is associated with enrichment in β-oxidation pathways, while OA exposure is associated with enrichment in anti-inflammatory and antioxidant pathways. Overall, this study further demonstrated that dietary PA and OA are important regulators of placental lipid metabolism. Encouraging appropriate dietary advice and implementing dietary interventions to maintain appropriate placental function by limiting excessive exposure to saturated NEFAs remain crucial in managing at-risk obese and GDM pregnancies.

Maternal obesity causes fetal cardiac hypertrophy and alters adult offspring myocardial metabolism in mice

Obesity in pregnant women causes fetal cardiac dysfunction and increases offspring cardiovascular disease risk, but its effect on myocardial metabolism is unknown. We hypothesized that maternal obesity alters fetal cardiac expression of metabolism-related genes and shifts offspring myocardial substrate preference from glucose towards lipids. Female mice were fed control or obesogenic diets before and during pregnancy. Fetal hearts were studied in late gestation (embryonic day (E) 18.5; term ≈ E21), and offspring were studied at 3, 6, 9 or 24 months postnatally. Maternal obesity increased heart weight and peroxisome proliferator activated receptor gamma (Pparg) expression in female and male fetuses and caused left ventricular diastolic dysfunction in the adult offspring. Cardiac dysfunction worsened progressively with age in female, but not male, offspring of obese dams, in comparison to age-matched control animals. In 6-month-old offspring, exposure to maternal obesity increased cardiac palmitoyl carnitine-supported mitochondrial respiration in males and reduced myocardial 18 F-fluorodeoxyglucose uptake in females. Cardiac Pparg expression remained higher in adult offspring of obese dams than control dams and was correlated with contractile and metabolic function. Maternal obesity did not affect cardiac palmitoyl carnitine respiration in females or 18 F-fluorodeoxyglucose uptake in males and did not alter cardiac 3 H-oleic acid uptake, pyruvate respiration, lipid content or fatty acid/glucose transporter abundance in offspring of either sex. The results support our hypothesis and show that maternal obesity affects offspring cardiac metabolism in a sex-dependent manner. Persistent upregulation of Pparg expression in response to overnutrition in utero might underpin programmed cardiac impairments mechanistically and contribute to cardiovascular disease risk in children of women with obesity. KEY POINTS: Obesity in pregnant women causes cardiac dysfunction in the fetus and increases lifelong cardiovascular disease risk in the offspring. In this study, we showed that maternal obesity in mice induces hypertrophy of the fetal heart in association with altered expression of genes related to nutrient metabolism. Maternal obesity also alters cardiac metabolism of carbohydrates and lipids in the adult offspring. The results suggest that overnutrition in utero might contribute to increased cardiovascular disease risk in children of women with obesity.

The mystery of the life tree: the placenta

The placenta is the interface between the fetal and maternal environments during mammalian gestation, critically safeguarding the health of the developing fetus and the mother. Placental trophoblasts origin from embryonic trophectoderm that differentiates into various trophoblastic subtypes through villous and extravillous pathways. The trophoblasts actively interact with multiple decidual cells and immune cells at the maternal-fetal interface and thus construct fundamental functional units, which are responsible for blood perfusion, maternal-fetal material exchange, placental endocrine, immune tolerance, and adequate defense barrier against pathogen infection. Various pregnant complications are tightly associated with the defects in placental development and function maintenance. In this review, we summarize the current views and our recent progress on the mechanisms underlying the formation of placental functional units, the interactions among trophoblasts and various uterine cells, as well as the placental barrier against pathogen infections during pregnancy. The involvement of placental dysregulation in adverse pregnancy outcomes is discussed.

Does membrane curvature elastic energy play a role in mediating oxidative stress in lipid membranes?

The effects of oxidative stress on cells are associated with a wide range of pathologies. Oxidative stress is predominantly initiated by the action of reactive oxygen species and/or lipoxygenases on polyunsaturated fatty acid containing lipids. The downstream products are oxidised phospholipids, bioactive aldehydes and a range of Schiff base by-products between aldehydes and lipids, or other biomacromolecules. In this review we assess the impact of oxidative stress on lipid membranes, focusing on the changes that occur to the curvature preference (lipid spontaneous curvature) and elastic properties of membranes, since these biophysical properties modulate phospholipid homeostasis. Studies show that the lipid products of oxidative stress reduce stored curvature elastic energy in membranes. Based upon this observation, we hypothesize that the effects of oxidative stress on lipid membranes will be reduced by compounds that increase stored curvature elastic energy. We find a strong correlation appears across literature studies that we have reviewed, such that many compounds like vitamin E, Curcumin, Coenzyme Q10 and vitamin A show behaviour consistent with this hypothesis. Finally, we consider whether age-related changes in lipid composition represent the homeostatic response of cells to compensate for the accumulation of in vivo lipid oxidation products.

Sex-specific responses in placental fatty acid oxidation, esterification and transfer capacity to maternal obesity

Fatty acid metabolism and oxidation capacity in the placenta, which likely affects the rate and composition of lipid delivered to the fetus remains poorly understood. Long chain polyunsaturated fatty acids, such as docosahexaenoic acid (DHA), are critical for fetal growth and brain development. We determined the impact of maternal obesity on placental fatty acid oxidation, esterification and transport capacity by measuring PhosphatidylCholine (PC) and LysoPhosphatidylCholine (LPC) containing DHA by mass spectrometry in mother-placenta-baby triads as well as placental free carnitine and acylcarnitine metabolites in women with normal and obese pre-pregnancy BMI. Placental protein expression of enzymes involved in beta-oxidation and esterification pathways, MFSD2a (lysophosphatidylcholine transporter) and OCTN2 (carnitine transporter) expression in syncytiotrophoblast microvillous (MVM) and basal (BM) membranes were determined by Western Blot. Maternal obesity was associated with decreased umbilical cord plasma DHA in LPC and PC fractions in male, but not female, fetuses. Basal membrane MFSD2a protein expression was increased in placenta of males of obese mothers. In female placentas, despite an increased MVM OCTN2 expression, maternal obesity was associated with a reduced MUFA-carnitine levels and increased esterification enzymes. We speculate that lower DHA-PL in fetal circulation of male offspring of obese mothers, despite a significant increase in transporter expression for LPC-DHA, may lead to low DHA needed for brain development contributing to neurological consequences that are more prevalent in male children. Female placentas likely have reduced beta-oxidation capacity and appear to store FA through greater placental esterification, suggesting impaired placenta function and lipid transfer in female placentas of obese mothers.

Revisiting preeclampsia: a metabolic disorder of the placenta

Preeclampsia (PE) is a leading cause of maternal and neonatal mortality and morbidity worldwide, impacting the long-term health of both mother and offspring. PE has long been characterized by deficient trophoblast invasion into the uterus and consequent placental hypoperfusion, yet the upstream causative factors and effective interventional targets for PE remain unknown. Alterations in the metabolism of preeclamptic placentas are thought to result from placental ischemia, while disturbances of the metabolism and of metabolites in PE pathogenesis are largely ignored. In fact, as one of the largest fetal organs at birth, the placenta consumes a considerable amount of glucose and fatty acid. Increasing evidence suggests glucose and fatty acid exist as energy substrates and regulate placental development through bioactive derivates. Moreover, recent findings have revealed that the placental metabolism adapts readily to environmental changes, altering its response to nutrients and endocrine signals; this adaptability optimizes pregnancy outcomes by diversifying available carbon sources for energy production, hormone synthesis, angiogenesis, immune activation, and tolerance, and fetoplacental growth. These observations raise the possibility that carbohydrate and lipid metabolism abnormalities play a role in both the etiology and clinical progression of PE, sparking a renewed interest in the interrelationship between PE and metabolic dysregulation. This review will focus on key metabolic substrates and regulatory molecules in the placenta and aim to provide novel insights with respect to the metabolism's role in modulating placental development and functions. Further investigations from this perspective are poised to decipher the etiology of PE and suggest potential therapies.

The impact of Di-(2-ethylhexyl) Phthalate and Mono(2-ethylhexyl) Phthalate in placental development, function, and pathophysiology

Di(2-ethylhexyl) phthalate (DEHP) is a chemical widely distributed in the environment as is extensively used in the plastic industry. DEHP is considered an endocrine disruptor chemical (EDC) and humans are inevitably and unintentionally exposed to this EDC through several sources including food, beverages, cosmetics, medical devices, among others. DEHP exposure has been associated and may be involved in the development of various pathologies; importantly, pregnant women are a particular risk group considering that endocrine alterations during gestation may impact fetal programming leading to the development of several chronic diseases in adulthood. Recent studies have indicated that exposure to DEHP and its metabolite Mono(2-ethylhexyl) phthalate (MEHP) may impair placental development and function, which in turn would have a negative impact on fetal growth. Studies performed in several trophoblastic and placental models have shown the negative impact of DEHP and MEHP in key processes related to placental development such as implantation, differentiation, invasion and angiogenesis. In addition, many alterations in placental functions like hormone signaling, metabolism, transfer of nutrients, immunomodulation and oxidative stress response have been reported. Moreover, clinical-epidemiological evidence supports the association between DEHP exposure and adverse pregnancy outcomes and pathologies. In this review, we aim to summarize for the first time current knowledge about the impact of DEHP and MEHP exposure on placental development and pathophysiology, as well as the mechanisms involved. We also remark the importance of exploring DEHP and MEHP effects in different trophoblast cell populations and discuss new perspectives regarding this topic.

Placental Compartmentalization of Lipid Metabolism: Implications for Singleton and Twin Pregnancies

The study of placental lipid metabolism in uncomplicated pregnancies has not been developed in the literature to date. Its importance lies in expanding the knowledge of placental function to enable comparison with pathological pregnancies in future research. The aim of the present study was to compare the lipid metabolic activity and storage of the maternal and fetal sides of the placenta in healthy pregnancies. Moreover, we compare singleton vs. twin pregnancies to determine if placental metabolic needs differ. We analyzed placental explants from uncomplicated pregnancies, 20 from singleton and 8 from bichorial-biamniotic twin pregnancies (n = 28). Six cotyledon fragments were collected from each placenta at different distances from the umbilical cord, three close to the chorionic plate (hereinafter, we will refer to them as "fetal side") and another three close to the anchoring villi into the decidua basalis (referred to as "maternal side"). The samples were analyzed for quantitative assay placental fatty acid oxidation (FAO) and esterification (FAE) activities and triglyceride levels. The location of lipid storage in the chorionic villi was assessed by Oil red-O staining. Placental fatty acid oxidation did not show differences when comparing the maternal and fetal sides of the placenta or between single and twin pregnancies. When comparing placental sides, FAE was increased twofold in the maternal side compared to the fetal side of the placenta (P = 0.013). The tendency for lipogenesis in the placenta was exemplified by the FAE/FAO ratio, which was a 37.1% higher on the maternal side (P = 0.019). Despite this, triglyceride levels were five times higher in the fetal side than in the maternal one (P = 0.024). When analyzing singleton vs. twins, FAE was superior in the fetal side in multiple pregnancies (× 2.6, P = 0.007) and the FAE/FAO ratio was significantly higher in twins than in singleton pregnancies, on both sides of the placenta. Despite this finding, triglyceride levels were similar in twin and singleton pregnancies. Comparing the placentas of twins in the same pregnancy, there were no differences in lipid metabolism (FAO or FAE) or placental triglyceride levels between the two co-twins. Using Oil red-O staining, lipid storage in chorionic villi was found to be located on the syncytiotrophoblast cells and not in the connecting axis. The maternal side of the placenta is more active in the esterification of fatty acids, while the storage of neutral lipids concentrates on the fetal side. Moreover, multiple gestations have increased esterification without changes in the concentration of placental triglycerides, probably due to a higher transfer to the fetal circulation in response to the greater energy demand from twin fetuses.

Placental fatty acid transport across late gestation in a baboon model of intrauterine growth restriction

KEY POINTS

Intrauterine growth restriction (IUGR) is associated with perinatal morbidity and increased risk of lifelong disease, including neurodevelopmental impairment. Fatty acids (FA) are critical for normal brain development, although their transport across the placenta in IUGR pregnancies is poorly understood. The present study used a baboon model of IUGR (maternal nutrient restriction, MNR) to investigate placental expression of FA transport and binding proteins, and to determine gestational age-related changes in maternal and fetal plasma FA concentrations. We found MNR to be associated with increased placental expression of FA binding and transport proteins in late gestation, with fetal plasma FA concentrations that were similar to those of control animals. The present study is the first to report a profile of fetal and maternal plasma FA concentrations in a baboon model of growth restriction with data that suggest adaptation of placental transport to maintain delivery of critically needed FA.

ABSTRACT

Intrauterine growth restriction (IUGR) is associated with specific changes in placental transport of amino acids, folate and ions. However, little is known about placental fatty acid (FA) transport in IUGR. We hypothesized that placental FA transport proteins (FATP) and FA binding proteins (FABP) are up-regulated and fetal plasma FA concentrations are decreased at term in a baboon model of IUGR. Pregnant baboons were fed control or maternal nutrient restricted (MNR) diet (70% of control calories) from gestation day (GD) 30 (term 184 days). Plasma and placental samples were collected at GD120 (control n = 8, MNR n = 9), GD140 (control n = 6, MNR n = 7) and GD170 (control n = 6, MNR n = 6). Placentas were homogenized, and syncytiotrophoblast microvillous plasma membrane (MVM) and basal plasma membranes (BM) were isolated. Protein expression of FABP1, 3, 4 and 5 (homogenate) and FATP2, 4, and 6 (MVM, BM) was determined by Western blotting. FA content in maternal and umbilical vein plasma was measured by gas chromatography-mass spectrometry. Placental FABP1 and FABP5 expression was increased in MNR compared to controls at GD170, as was MVM FATP2 and FATP6 expression at GD140 and FATP2 expression at GD170. BM FATP4 and FATP6 expression was increased in MNR at GD140. Fetal plasma FA concentrations were similar in controls and MNR. These data suggest the adaptation of placental transport when aiming to maintain delivery of critically needed FAs for fetal growth and brain development.

Metabolism of 13C-Labeled Fatty Acids in Term Human Placental Explants by Liquid Chromatography-Mass Spectrometry

Placental lipid transport and metabolism are poorly understood despite the importance for fetal development and lifelong health. We aimed to explore fatty acid (FA) processing in human villous placental explants from seven uncomplicated term singleton pregnancies delivered by elective cesarean section. Explants were treated with stable isotope-labeled palmitic acid (13C-PA), oleic acid (13C-OA), or docosahexaenoic acid (13C-DHA) for 3, 24, or 48 hours. Stable isotope-labeled lipids synthesized by placental explants from labeled FA were quantified, alongside endogenous unlabeled placental lipids, by liquid chromatography-mass spectrometry. Labeled phosphatidylcholines (PCs), triacylglycerols (TAGs), and phosphatidylethanolamines were detected in explants, whereas labeled lysophosphatidylcholines were found in both explants and conditioned media. 13C-PA was primarily directed into PC synthesis (74% of 13C-PA-labeled lipids), whereas 13C-OA was directed almost equally into PC and TAG synthesis (45% and 53%, respectively, of 13C-OA-labeled lipids). 13C-DHA was only detectable in TAGs. TAGs demonstrated the highest isotopic enrichment for all 13C-FAs with 13C-OA-TAGs comprising >50% of total OA-TAGs (unlabeled and labeled), consistent with TAGs being a labile and accessible reservoir for FA storage. Variations in lipid incorporation were correlated to maternal glycemia and body mass index, suggesting that this experimental model could be used to investigate the effect of maternal factors on placental lipid metabolism. We conclude that lipid metabolic partitioning of freshly imported FAs into labile and less labile lipid reservoirs in placenta is FA dependent. This process may partly mediate the physiological preferential transplacental transfer of particular FAs to the fetus, but may also be implicated in the fetoplacental pathophysiology of maternal metabolic dysfunction.

Maternal obesity results in decreased syncytiotrophoblast synthesis of palmitoleic acid, a fatty acid with anti-inflammatory and insulin-sensitizing properties

The fetus is dependent on delivery of fatty acids (FAs) by the syncytiotrophoblast, the transporting epithelium of the human placenta. Obese pregnant women have dyslipidemia; however, whether obesity impacts placental lipid transport and metabolism remains to be fully established. Palmitoleic acid (POA), an FA with anti-inflammatory and insulin-sensitizing properties, is synthesized from palmitic acid (PA) catalyzed by stearoyl-coenzyme A desaturase (SCD) activity. We hypothesized that the uptake and incorporation of FAs and POA synthesis are reduced in primary human trophoblasts (PHTs) isolated from pregnancies complicated by maternal obesity. Villous cytotrophoblasts were isolated from 7 placentas of obese [body mass index (BMI) = 37.5 ± 1.9] and 12 normal (BMI = 23.6 ± 0.6) mothers. FA uptake and incorporation were assessed using uniformly labeled (U[¹³C])-FA mixtures of PA, oleic acid (OA), linoleic acid, and docosahexaenoic acid. Cellular [¹³C] FAs were quantified both in total cellular lipids and in lipid classes by GC-MS. Uptake and incorporation of [¹³C] FAs in total cellular lipids were not different in PHTs isolated from obese mothers compared with normal mothers. Only the concentration of OA was increased in the triglyceride fraction (P < 0.05) if the mother was obese. We found an isotopic enrichment of POA after U[¹³C]-PA treatment, demonstrating SCD activity in PHT cells. Labeled POA content and the POA:PA ratio were significantly lower in PHTs isolated from placentas of obese mothers compared with normal, healthy controls. Decreased syncytiotrophoblast POA synthesis may contribute to insulin resistance and low-grade inflammation in the mother, placenta, or fetus (or a combination of the 3) in pregnancies complicated by obesity.-Ferchaud-Roucher, V., Barner, K., Jansson, T., Powell, T. L. Maternal obesity results in decreased syncytiotrophoblast synthesis of palmitoleic acid, a fatty acid with anti-inflammatory and insulin-sensitizing properties.

Maternal dietary ratio of linoleic acid to alpha-linolenic acid during pregnancy has sex-specific effects on placental and fetal weights in the rat

Background

Increased consumption of linoleic acid (LA, omega-6) in Western diets coupled with the pro-inflammatory and adipogenic properties of its derivatives has led to suggestions that fetal exposure to this dietary pattern could be contributing to the intergenerational cycle of obesity.

Method

This study aimed to evaluate the effects of maternal consumption of a LA to alpha-linolenic acid (ALA) ratio similar to modern Western diets (9:1) compared to a lower ratio (1:1.5) on placental and fetal growth, and to determine any cumulative effects by feeding both diets at two total fat levels (18% vs 36% fat w/w). Female Wistar rats (n = 5–7/group) were assigned to one of the four experimental diets prior to mating until 20d of gestation.

Results

Fatty acid profiles of maternal and fetal blood and placental tissue at 20d gestation were different between dietary groups, and largely reflected dietary fatty acid composition. Female fetuses were heavier (2.98 ± 0.06 g vs 3.36 ± 0.07 g, P < 0.01) and male placental weight was increased (0.51 ± 0.02 g vs 0.58 ± 0.02 g, P < 0.05) in the low LA:ALA groups. Female fetuses of dams exposed to a 36% fat diet had a reduced relative liver weight irrespective of LA:ALA ratio (7.61 ± 0.22% vs 6.93 ± 0.19%, P < 0.05). These effects occurred in the absence of any effect of the dietary treatments on maternal bodyweight, fat deposition or expression of key lipogenic genes in maternal and fetal liver or maternal adipose tissue.

Conclusion

These findings suggest that both the total fat content as well as the LA:ALA ratio of the maternal diet have sex-specific implications for the growth of the developing fetus.

Alterations in placental long chain polyunsaturated fatty acid metabolism in human intrauterine growth restriction

Fatty acids (FA) are critical for fetal brain development and are transferred across the placenta by membrane-bound FA transport proteins (FATP), translocases (FAT/CD36), and cytosolic binding proteins (FABP). The cytosolic protein perilipin-2 aids in neutral lipid storage within lipid droplets. Decreased placental nutrient transport is believed to contribute to intrauterine growth restriction (IUGR); however, IUGR placental lipid transport and metabolism are poorly understood. We hypothesized that protein expression of FATPs, FABPs, and perilipin-2 in human placenta is decreased and placental lipid content and incorporation into lipid classes are reduced in IUGR. Placental tissue of idiopathic IUGR (n=25) and gestational age-matched, appropriately grown for gestational age (AGA) fetuses (n=19) was collected. We determined protein expression of FABP4 and perilipin-2 in placental homogenate and FATPs (2, 4, 6, CD36) in syncytiotrophoblast microvillous plasma membrane (MVM) by Western blot. Lipid droplet area (Oil Red O stain) and cellular FA content (GC/MS) were measured in chorionic villous tissue. MVM expression of FATP6 and CD36 was significantly increased in IUGR. The concentrations of seven n-6 and n-3 species long chain polyunsaturated FAs (LCPUFA) were significantly increased in the triglyceride fraction in IUGR vs AGA placenta. In summary, MVM FATP6 and CD36 protein expression is increased and LCPUFA are preferentially routed toward cellular storage in TG in the IUGR placenta, possibly to protect against oxidative stress associated with cellular FA accumulation. We speculate that these changes may be caused by impaired efflux of FA across the fetal-facing syncytiotrophoblast basal plasma membrane in IUGR placenta.

Placental fatty acid transfer

PURPOSE OF REVIEW

This review outlines recent advances in placental lipid transport in relation to maternal metabolic status and pregnancy outcome. A particular focus of this review will be on the way these findings may influence our understanding of placental transfer of the essential fatty acid docosahexaenoic acid (DHA) which is crucial for fetal neurodevelopment and of lipid transfer as a predisposing factor for childhood obesity.

RECENT FINDINGS

Placental metabolism may determine the quantity and composition of fatty acids delivered to the fetus. Maternal factors, such as obesity, appear to regulate placental lipid metabolism and may influence fatty acids delivery to the fetus. Although the role of placental metabolism is now recognized, new evidence also suggests important roles for nontraditional fatty acid transporters such as Mfsd2a which facilitates transfer of DHA.

SUMMARY

Placental lipid metabolism is likely to be a determinant of placental transfer of fatty acids to the fetus. Maternal conditions, such as obesity, have now been shown to regulate placental lipid metabolism and thus may influence fatty acid transfer and fetal development. However, it is not yet clear how regulation of placental lipid metabolism affects fatty acid delivery to the fetus and its long-term health.